Considerable progress has been made in determining psychosocial-behavioral processes in smoking in early adolescence (junior high school) and developing interventions to deter the relatively infrequent smoking in this age group. Inadequately addressed is the problem of the increased acceleration of smoking in later adolescence (senior high school), a period during which more frequent smoking becomes evident. Some students maintain abstinence or infrequent smoking; other increase smoking frequency, many becoming dependent smokers. Objectives of 9th, 10th and 11th grade cross-sectional and prospective investigation would be: 1) to determine from a pre-intervention cross-sectional survey of a representative sample of 9th, 10th and 11th grade students (n=1440) the cognitive-psychosocial-behavioral processes related to smoking as students progress through high school; 2) based partly on these pre-intervention data, our earlier experience with junior high school programs, concepts from developmental and social psychology, to develop, implement and evaluate in 12 high schools (n=500 each) randomly assigned to various intervention and control conditions, a specially designed smoking deterrence program. This program would encompass information and strategies for coping with pressures to smoke in 12 discussion trigger films, discussion, personal involvement techniques and feedback. Within a modified time-series design, dependent measures would include indicators of smoking frequency and cognitive-psychosocial-behavioral factors which relate to and influence smoking over time. Appropriate covariate and multivariate statistical procedures would be used in the analysis of the data. Information would be gained concerning: 1) how various cognitive-psychosocial-behavioral processes among late adolescents are related to continued smoking abstinence or infrequent smoking in some students and smoking acceleration in others; 2) the efficacy of an intervention strategy designed to deter the acceleration of smoking through the high school years including how effectively teachers with or without special training compared with research staff can deliver this intervention.